chapter 1-dmc 101-basic concepts

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CHAPTER 1: BASIC CONCEPTS

Chemistry:

"The study of the properties of materials and the

changes that materials undergo"

INTRODUCTION TO MATTER

1. Matter"Matter is the physical material of the universe;

it is anything that occupies space and has

mass"

Audi Majdan – DMC 101 – KLIUC 1



• Matter can be divided into pure substance

or mixture

2. Substances

• A pure substance has a fixed composition

and unique properties.• Most matter in our daily lives is not a pure

substance, but a mixture of substances.

• Pure substances are composed of either

elements or compounds.

2.1 Elements

• Definition : Substances which cannot be

decomposed into simpler substances by

chemical means

Audi Majdan – DMC 101 – KLIUC

Matter

SubstanceMixture

(2 or more substances)

ElementCompound

(2 or more elements)

2



• Basic substances for all matter

• Everything in the world is made up from

only 109 different elements.• 90% of the human body is composed of only

three elements: Oxygen, Carbon and

Hydrogen

• Example of elements:

Element Abbreviation

Carbon C

Fluorine F

Hydrogen H

Iodine I

Nitrogen NOxygen O

Phosphorus P

Sulfur S

Aluminum Al

Barium BaCalcium Ca

Chlorine Cl

Helium He




Magnesium Mg

Platinum Pt

Silicon Si

Copper Cu (from

cuprum)

Iron Fe (from ferrum)

LeadPb (from

plumbum)

MercuryHg (from

hydrargyrum)

Potassium K (from kalium)

Silver Ag (from

argentum)

Sodium Na (fromnatrium)

TinSn (from

stannum)

2.2 Compounds

• Definition : Substance composed of two or

more elements.




• United chemically in definite proportions

by mass. For example: pure water is

composed of the elements hydrogen (H) and

oxygen (O)

3. Mixtures

• Definition : combinations of two or more

substances in which each substance retainsits own chemical identity and hence its own

properties.

• Heterogenous mixtures are not uniform

throughout the sample and have regions of

different appearance and properties

Example: Mixture of water and oil




• Homogenous mixtures are uniform

throughout the sample and individual

substances retain their individual chemical

and physical nature.

• Homogenous mixtures are also called

solutions; the most common type of solution

is described by a solid (the solute) dissolved

in a liquid (the solvent ).

Example: Solution of water and sugar

• Individual components of mixtures retain

their physical and chemical properties.

• → the components can be separated .




• For example: ethanol can be separated from

water by using distillation process.

• Miscible – two liquids that dissolve in one

another without separating into layers

• Immiscible – two liquids that do not mix

and form into separate layers.

Physical States of Matter

• Matter can exist in 3 physical states:

1. Gas

2. Liquid

3. Solid

Gas

• No fixed volume or shape - it takes the

volume and shape of its container.

• Can be compressed or expanded to occupy

different volumes.

Liquid

• Has a distinct volume

• No specific shape

• Takes the shape of the container




• Cannot be compressed

Solid

• Has a definite shape and volume

• Rigid

• Cannot be compressed

Physical and Chemical Properties


SOLID

LIQUID

GAS

Definite

volumeDefinite

Rigid

definitevolume

NO definite

shape

NO distinct

volume NO distinct

shape

Can be

compressed

MATTER



• Every pure substance has a unique set of

properties - characteristics which allow us to

distinguish it from other substances.

• 2 general properties: physical and chemical .

Physical properties = properties that can be

measured without changing the basic identity of

the substance.

Example: Colour, hardness & density.

Chemical properties = properties of a

substance that may change or "react" to form

other substances.

Example: to explode, to combust.

Physical and Chemical Changes

• Substances can undergo various changes in

properties; either physical or chemical.

• Physical changes - a substance changes its

physical appearance but not its basic

identity. All changes of state (e.g. solid toliquid to gas) are physical changes.




• Chemical changes (or chemical reactions)

– a substance is transformed into a

chemically different substance.


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